<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
    <style>
        .one,.two{
            width:400px;
            height:200px;
            margin-bottom:30px;
        }
        .one{
            background-color:red;
            position:relative;      /*不占位置*/
            left:30px;
        }
        .two{
            background-color:pink;
             position:relative;
            left:30px;
            top:30px;          /*以自己为基准进行移动*/
        }
        span{
            width:30px;
            height:30px;
            background-color:orange;
            position:relative;              /*相对定位不能进行模式的转换*/
        }
    </style>
</head>
<body>
   <!--<div class="one"></div>
   <div class="two"></div>-->
   <span>hsdkfhksdj</span>
</body>
</html>